Method of manufacturing straw pulp and paper



whole as well as to the resulting paper.

Patented Sept. 4, 1928.

UNITED STATES 1,682,834 PATENT orncs.

CHARLES H. IVEIIZWICK, OI DBEXEL HILL; PENNSYLVANIA, AQBIGNOR TO PHILADEL- PHIA QUARTZ comm, A CORPORATION 01 PENNSYLVANIA.

METHOD OF IANUFACTURING STRAW PULP AND PAPER.

110 Drawing.

This invention relates to the paper makin art and especially to an improved method 0 making and treating the pulp whereby to secure certain advantages to the process asI? is particularly useful in the manufacture of paper from straws, such as rye wheat or oat straws, or from any other suitable vegetable fibre.

It has for its rincipal objects the provision of a method which will y eld a maximum amount of paper from a given amount of straw while at the same time keeping the chemical cost within a reasonable figure; which will lend or adapt itself with great flexibility and consequent economy to the limitations of individual plants; which will be productive of a saving in the timerequlred to produce a paper; which will elim nate certain of the ste s heretofore essential in the manufacture 0 paper; which will reduce the quantity of objectionable efiluent from the pulp making process and simplify the prob 'lem of disposin of the waste water; and, in

general, one which will improve the efficiency of the plant and the quality of the product.

Heretofore, the usual procedure in manufacturing pulp from straw has involved cooking the straw with lune and the necessary amount of water. Subsequently the lime had to be washed from the pulp before beating was begun and at frequent intervals the process has had to be interrupted to permit washing of the apparatus with hydrochlorlo acid due to certain objectionable characterist cs of the lime with which those skllled 1n this art will be entirely familiar. Furthermore, 1n washing out the lime all of the dissolved oranic matter or intercullular substance of t e straw has heretofore been removed.

As contrasted with this customary procedure I provide a method in which all or a large pro ortion of the washlng before heating may e dispensed with and 1n WhlCll n o interruptions for washin with hydrochlorlc acid are necessary. I a so make it posslble to use art or all of the actual cooking liquor in the beater thereby permitting retention of dissolved organic matter from the straw which, in combination with the residual quantity of the active agent in the cooking 11 nor, (as will appear erelnafter) can be an sequently set to act as a sizing for the paper.

With the foregoing in mind morespecific Application filed January 6,1925. Serial No. 808.

objects of the invention are the provision of a method of manufacturing pulp and paper whlch Wlll ield a harder, stronger paper than hereto ore possible, which will be capable of a high finish and be exceptionally water-resistant; the revision of a method which revents loss 0 fibre due to washing of the pa p and the provision of a method WhlOh will increase the beater capacity of a plant.

In obtaining all of the foregoin advantages and results I proceed as fol ows: Instead of using lime I prepare the pul by cooking the straw with a solution of silicate of soda. Silicate of soda alone is preferable but lts benefits may be secured in association with other alkaline or neutral com ounds such as caustic soda or sodium car nate. After the cooking is completed the mass is drained to remove any excess quantity of the cooking liquor and then placed in any one of the well known devices known to the art for beatlng or preparing the pulp. To this is added the necessary water and some of the cookin liquor. Beating or preparation of the pu p re then begun and it will be noted that washing prior to beating is not necessary as it is with the lime process. Of course,

if preferred the cooked mass may be washed ust enough to remove the excess cooking liquor but it is not necessary to wash at all as draining alone will suifice, the purpose bein simply to make it possible to more easily an accurately proportion the batch for the beater since water and some of the cooking liquor are to be added. The step described as drainmg may in some cases be omitted altogether and the pulp transferred directly from the cooking vessel to the beater without the removal of any of the cookin liquor.

hen beating is comp etc or nearly so a quantity of aper-makers alum somewhat more than an cient to react with the silicate 1n the pulp is added to the heater and thoroughly mixed after which the mass may be diluted with water and formed into paper in aggordance with the usual practices in this a It will thus be seen that by my process I am Furthermore, because of the fact that I can make use of some of the cooking liquor in the-beater I am enabled to retain a portion of the dissolved organic matter of the straw, the intercellular stufis or materials from the straw having been carried into the solution during cooking with the silicate of soda.

This dissolved organic matter plus the residual silicate are precipitated on the fibre actin as a sizing for the'paper which is set b t e aper-makers alum (AI,(SO,),). 'lqiis ren era the paper water-resistant and tough without interfering with its flexibility. A water resistant paper can, therefore, be obtained by my process at a sli ht cost for alum and by dispensing with t e washing before beating and using the alum in the beater it is possible to effect a large saving of the finer fibre and at the same time to greatly reduce the quantity of objectionable organic matter going into the efliuent.

While I prefer to use alum as the precipitating material other equivalent substances might be used for some papers, for instance the sulphates of iron. Certain acids and acid salts have been proposed for precipitation of size and my invent on is not to be considered as limited to the use of paper makers alum onl l y preparing the pulp in the manner herein disclosed the fibre produced is short and hard with much of the'intercellular stufLof the straw removed but with sufiicient having been retained to aid in lending to the paper the desirable characteristics above mentioned.

It is highly hydrated and capable of a higher finish when made into pa er than when made by the old lime process. urthermore, b my method, I have found that it is possib e to substantially reduce the average cooking time.

While a great variety of silicates might be used in producing my improved results I have found that a silicate of approximately the following comsosition is preferable, namely, Na,O3.25Si V An important advantage of my process resides in its elimination of the necessity for washing the machines with hydrochloric acid. In the old lime rocess certain objectionable characteristics oi the lime, well lmown in this art, required such washings with their incidental expense and loss of time. I, therefore, increase plant economy and efliciency in this we also.

carrying out m invention a very eat latitude is permissib e in the amount 0 silicate used and the time allowed for cooking and beatin Cooking temperatures also may vary consi erably. In eneral it may be said that the time for coo g varies lnversely with the quantity of silicate. If chemical al consumption ha pens to be afactorof major importance at e time less than the average amount of silicate might be used with a certain corresponding'increase in the length of the cooking period but when time ha'pens to be of more value than the cost of t e reagent a greater amount of silicate with a shorter cooking period would be desirable. Also, the cooking may be accomplished by (ripen boiling or by steam at various pressures. o definite times or figures are believed to be necessary and, indeed, it would be almost im ossible to la down any fixed rules for in ividual conditions and requirements, are so widely variant. Adetermination in each instance must fall as usual within the rsonal judgment of each individual. In a 12 series of ex riments invol many di ferences in time and materials, was able to produce manyppgglrers of excellent qualig.

and as an'exam cite the following whi gave a very hard, flexible and water-resists ant sheet 50 parts by weight of straw were mixed with 500 parts by weight of water and 5 parts by wei ht of sihcate of soda and then steam cooked or eight hours at a pressure of 40 lbs. The silicate used was a 40 percent solution of the preferred composition and the cooking temperature was 130 centigrade. The pulp thus produced was beaten or 5 4 hours and after the addition of the alum a aper was made.

A pu p made in accordance with this invention is especially fitted for making corrugated paper and other forms of paper used in the shipping container industry where rigidity an ow cost are important.

. I claim 1. In the manufacture of aper the method of pre arin the pulp whic comprises cooking with silicate of soda, beating with cooking liquor, and then 2. In the manufacture 0 paper the method which includes cooking the bre with silicate of soda and beating without washing.

3. In the manufacture of aper the method which includes cooking the bre with silicate of soda, in removing the excess liquor but not necessarily eliminating all of it, in heating with water and a rtion ofthe li uor, and in sizing b precipitating on the bre the residual silicate with its contained organic matter.

4. In the manufacture of aper the method which includes cooking the fibre with silicate of soda and beating with cooking liquor.

5. The method of manufacturing aper which includes cooking straw with s1 'cate of soda, in beating the pulp with liquor, and in adding paper makers alum.

6. In the manufacture of aper the method of preparing the pulp whic comprises cooking with sihcate of soda, beating with cool:- ing liquor and treating with paper-maker's 7. In the manufacture of aper the method which'includes cooking the bre with silicate of soda, beating with cooking liquor and aizing by precipitating with alum the residual silicate. I

8. In the manufacture of aper the method which includes cooking the fibre with silicate of soda, heating with cookin liquor and siz: ing by precipitating with a um the residual i silicate with its dissolved organic content.

9. In the manufacture of aper the method which includes cooking the fibre with silicate of soda, heating with cookin liquor and sizing by precipitating on the bre the residual sihcate with its contained organic matter.

10. As a new article of manufacture, a paper prepared from pulp cooked with silicate of soda and beaten with a portion of the 15 cooking liquor.

11. As a new article of manufacture, a paper prepared from straw pulp cooked with silicate of soda, and sized by precipitation of the residual silicate plus the contained cr- 2o ganic matter.

In testimony whereof, I have hereunto signed my name.

CHARLES H. DEDRIGK. 

